CN113196185B - Position adjustment control to compensate for spring-dependent position errors - Google Patents

Abstract

A control command (C) for a control device (4) of the machine is provided, the control command (C) determining a sequence of ideal position target values (x) for a position adjustment shaft (1) of the machine. The sequence has successive segments in turn. Within a segment, the ideal position target value (x) monotonically increases or monotonically decreases. The monotonic direction is shifted from segment to segment. The control device (4) implements the position controller (13) and delivers the resulting position target value (x+δx) and the position actual value (x) to the position controller (13) in accordance with the sequence of the ideal position target value (x). The position controller (13) generates an actuation signal (v) for the actuator (12) of the shaft (1) and adjusts the position (x) of the respective shaft (1) accordingly. The resulting position target value (x+δx) corresponds to the sum of the ideal position target value (x) and the additional target value (δx). In the segment, if the ideal position target value (x) monotonically increases, the additional target value (δx) is a positive number. If the ideal position target value (x) monotonically decreases, the additional target value (δx) is negative. The additional target value (δx) comprises a first component (δx1), the first component (δx1) being related only to the position difference. The position difference is the corresponding ideal position target value (x) and the first ideal position target value (x) of the corresponding section or the difference between the corresponding ideal position target value (x) and the corresponding position actual value (x). The absolute value of the first component (δx1) of the additional target value (δx) increases strictly monotonically with increasing absolute value of the position difference and at least monotonically thereafter.

Description

Position control to compensate for elasticity-related position errors

Technical Field

The invention relates to a control method for a machine having at least one position-controlled axis.

In this case, a control device of the machine predetermines a sequence of control commands which determines a sequence of ideal position target values for at least one position-controlled axis.

- wherein the sequence of ideal position target values has a plurality of successively consecutive sections,

wherein, within a corresponding section of the sequence of ideal position target values, the ideal position target value increases monotonically or decreases monotonically,

- wherein the differences of the directly consecutive ideal position target values change their sign from one section to another of the sequence of ideal position target values,

- wherein the control device implements a position controller for at least one position-regulating axis,

- wherein the control device supplies a sequence of resulting position target values and corresponding actual position values to the position controller based on the sequence of ideal position target values,

- wherein, as a function of the respective resulting position target value supplied to the position controller and the respective actual position value supplied to the position controller, the position controller derives a respective first actuation signal for an actuator of the at least one axis and thereby directly or indirectly regulates the position of the at least one axis as a function of the respective resulting position target value,

- wherein the corresponding result position target value is obtained by adding the corresponding additional target value to the corresponding ideal position target value,

- wherein, within a section of the sequence of ideal position target values, if the ideal position target value increases monotonically, the corresponding additional target value is a positive number, and if the ideal position target value decreases monotonically, the corresponding additional target value is a negative number.

Furthermore, the invention relates to a control program for a control device of a machine, the control device having at least one position-adjusting axis, wherein the control program comprises a machine code which is processed directly by the control device, wherein the processing of the machine code is caused by the control device such that the control device controls the at least one position-adjusting axis according to such a control method.

The invention further relates to a control device for a machine having at least one position-controlled axis, wherein the control device is programmed with such a control program, wherein during operation the control device controls the at least one position-controlled axis according to such a control method.

Furthermore, the invention relates to a machine, wherein the machine has at least one position-controlled axis, wherein the machine has such a control device, so that during operation the control device controls at least one position-controlled axis of the machine according to such a control method.

Background technique

In all cases, forces occur in the position adjustment of axes, which are caused by friction. In order to produce the actual travel movement, the friction forces must be overcome. Furthermore, no mechanical structure (nor any axis of a machine tool, robot or other production machine) has infinite rigidity. Therefore, (even if relatively small) elastic deformations occur.

One, the position sensor detects the position of an object moving by means of an axis (e.g. TCP = Tool Center Point), which accurately detects not the position of the object but the position of the actuator, i.e. the drive of the object moving by means of the axis. If the position indicated by the position sensor corresponds exactly to the preset target position, the actual position of the object moving by means of the axis deviates from the target position due to elastic deformation. In the technical field, this effect is usually referred to as "lost motion" or missing motion.

However, in order to be able to detect the actual position of the object, in some cases another measuring system is used, which is arranged as close as possible to the moving object (such as the mentioned TCP). However, in many cases, the arrangement of such a measuring system near the moving object is not feasible or cannot be performed. In this case, the so-called lost motion must be accepted.

In the prior art, different types of compensation have also been considered. In particular, it is known that on shafts that include transmissions, the gear meshing backlash that occurs when the direction of movement changes is compensated by an additional target value that is added to the position target value (or to the position actual value with an opposite sign). In this method, the additional target value has a constant value within the corresponding section of the ideal position target value sequence. However, these methods often lead to more problems than they solve.

A control method for a machine having at least one position regulating axis is known from EP 3 208 669 A1. The axis is a round axis, so that the position is a rotational position. A control device of the machine predetermines a sequence of control commands, which sequence determines a sequence of ideal position target values for at least one position regulating axis. The control device implements a position regulator for at least one position regulating axis and, depending on the sequence of ideal position target values, the control device delivers a sequence of resultant position target values and corresponding position actual values to the position regulator. The corresponding resultant position target value is obtained by adding a modification value to the corresponding ideal position target value. The modification value is related to the rotational position and the rotational speed of the position regulating axis.

Summary of the invention

The object of the present invention is to provide a possibility by means of which a good compensation of lost movements can be achieved not only on shafts that include a gear mechanism, but on shafts in general.

This object is achieved by a control method having the features of the present invention. Advantageous embodiments of the control method according to the present invention are the subject matter of the various exemplary embodiments.

According to the invention, a control method of the type mentioned at the outset is designed as follows:

the additional target value comprises a first component which is only related to the position difference,

The position difference value is the difference between the corresponding ideal position target value and the first ideal position target value of the corresponding segment or the difference between the corresponding ideal position target value and the corresponding position actual value and

With increasing absolute values of the position difference values, the absolute value of the first component of the additional target value rises strictly monotonically at the beginning and at least monotonically thereafter.

By engaging the additional target value, at least one position-controlled axis can thus be moved significantly beyond its actual target position. However, due to the hysteresis of the axis, that is, behind the output signal of the position sensor arranged on the actuator, the desired position is accurately approached with a suitable choice of the additional target value. However, sudden target value jumps are prevented by the gentle, gradual engagement of the respective additional target value with the respective ideal position target value. The resulting movement of the axis becomes gentle and soft.

Preferably, as soon as the absolute value of the position difference reaches a limit, the absolute value of the first component assumes a predefined maximum value and then remains constant within the corresponding section of the sequence of ideal position target values. In this way, hysteresis errors can be compensated in a nearly ideal manner.

Preferably, the first component has the value zero at the beginning of the respective segment of the sequence of ideal position target values. In particular, a continuous transition for the compensation of the hysteresis error is achieved by this method.

Furthermore, it is advantageous if the additional target value comprises a second component, which is related to the travel speed of the at least one axis. In particular, the second component can be proportional to the travel speed of the at least one axis. This approach is based on the fact that friction forces often have a speed-dependent component. Therefore, in addition to force-dependent lost movements, there are also speed-dependent lost movements. By means of the second component, the speed-dependent component of the lost movement can be compensated in an approximately ideal manner. The provision of the second component can in principle replace the provision of the first component. However, the second component is usually present in addition to the first component.

The control device usually implements a speed regulator attached to the position regulator. In this case, the position regulator does not directly supply the respective first actuation signal to the actuator. Rather, the position regulator supplies the respective first actuation signal with the resulting speed target value and also with the respective speed actual value to the speed regulator, wherein the respective resulting speed target value is dependent on the respective first actuation signal. In this case, the speed regulator determines the respective second actuation signal for the actuator of the at least one axis as a function of the respective resulting speed target value and the respective speed actual value and thereby directly or indirectly regulates the speed of the at least one axis as a function of the respective resulting speed target value.

In the simplest case, the resulting speed target value is identical to the corresponding first actuation signal. However, this generally leads to a better control behavior if the control device derives the corresponding first precontrol signal from the sequence of resulting position target values without taking into account the corresponding actual position value and derives the corresponding resulting speed target value by adding the first precontrol signal to the corresponding ideal speed target value.

Generally, a better control behavior results if the control device derives a corresponding second precontrol signal from the sequence of resulting position target values without taking into account the corresponding position actual value, and the speed regulator does not directly supply the corresponding second actuation signal to the actuator, but the control device derives a corresponding third actuation signal for the actuator by adding the corresponding second precontrol signal to the corresponding second actuation signal. In this case, the actuator is actuated according to the corresponding third actuation signal or according to a corresponding fourth actuation signal derived from the corresponding third actuation signal.

Particularly good results result if the control device derives a respective third pilot control signal from the sequence of additional target values without taking into account other changing values and derives a respective fourth actuation signal for the actuator by adding the respective third pilot control signal to the respective third actuation signal. In this case, the actuator is actuated with the respective fourth actuation signal.

If the corresponding first pilot control signal is not added to the corresponding first actuation signal and/or the second pilot control signal is not added to the corresponding second actuation signal, it is also possible to add the corresponding third pilot control signal. In this case, the control device derives the corresponding result actuation signal for the actuator by adding the corresponding third pilot control signal to the corresponding second actuation signal, and uses the result actuation signal to control the actuator.

The object is further achieved by a control program having the features of the invention. According to the invention, a control program of the type mentioned at the outset is designed to cause processing of a machine code by a control device which controls at least one position-controlled axis according to the control method of the invention.

The object is further achieved by a control device having the features of the invention. According to the invention, a control device of the type mentioned at the outset is programmed with a control program according to the invention such that during operation the control device controls at least one position-controlled axis according to the control method according to the invention.

Furthermore, the object is achieved by a machine having the features of the invention. According to the invention, the control device of the machine is designed according to the invention such that during operation the control device controls at least one position-controlled axis according to the control method according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned characteristics, features and advantages of the present invention and the ways and methods of how to achieve them are explained in more detail below based on the description of the embodiments in conjunction with the accompanying drawings. Here, it is shown in a schematic diagram:

FIG1 shows a machine with multiple position-adjustable axes.

Figure 2 shows the sequence of ideal position target values,

Figure 3 shows the position adjustment of a single position adjustment axis.

FIG4 shows the functional distribution of the first component of the additional target value,

FIG5 shows the functional distribution of FIG4 for positive and negative position differences,

FIG6 shows the functional distribution of the second component of the additional target value and

7 to 9 show modifications of the position adjustment of FIG. 3 .

Detailed ways

According to FIG. 1 , the machine has a plurality of position-adjustable axes 1. According to the schematic diagram in FIG. 1 , the machine can be, for example, a machine tool, so that by means of the position-adjustable axes 1, a tool 2 of the machine tool is translationally positioned and/or rotationally oriented relative to a workpiece 3 to be processed. However, the machine can alternatively also be another machine, for example a robot with a flexible arm or a processing machine or other production machine. It is essential that the machine (in the numerical sense) has at least one position-adjustable axis 1.

The machine has a control device 4, which controls the machine. The control device 4 is a digital controller (CNC) or a motion controller. The motion controller is very similar to the digital controller in terms of its function. Basically, the difference is only in the application, that is, the digital controller is used to control machine tools, and the motion controller is used to control robots or other machines. However, in both cases (digital controller and motion controller), the position control of at least one position control axis 1, usually a plurality of position control axes 1, is realized.

The control device 4 is software programmable. Therefore, the control device 4 is programmed with a control program 5. The control program 5 corresponds to a system program for the control device 4. The control program 5 includes a machine code 6. The machine code 6 can be processed directly by the control device 4. The processing of the machine code 6 is caused by the control device 4 so that the control device 4 controls at least one position-controlled axis 1 according to a control method, which will be explained in detail later.

For the sake of good order, it should be mentioned that according to the control method explained later, the control device 4 can also control all position adjustment axes 1 of the machine or at least a plurality of position adjustment axes 1 according to the control method explained below as needed. It is essential that this is implemented in at least one position adjustment axis 1. Therefore, only the control method for one of the position adjustment axes 1 is explained later. Therefore, only "position adjustment axis 1" is always discussed later. If a control method for a plurality of or all position adjustment axes 1 is implemented, it is usually implemented in the same way for all such axes 1. However, this is not mandatory. It is possible to implement different designs of the present invention for each position adjustment axis.

The control device 4 is preset with a sequence of control commands C. The control commands C determine a sequence of ideal position target values x* for the position-controlled axis 1. For example, the control commands C of the control device 4 can be preset with the aid of a subroutine 7 which defines a sequence of corresponding position target values x* for a plurality of axes 1 of the machine that is coordinated with one another, so that the coordinated sequence defines the path traveled by the tool 2 relative to the workpiece 3 and thus defines for each axis 1 a sequence of position target values x* that are closely successive with one another for the respective axis 1.

The ideal position target value x* follows each other as a function of time t with a small, usually constant time interval δt. The sequence of the ideal position target value x* has a plurality of consecutive sections according to the schematic diagram in FIG. 2. The boundary of the section is shown by a vertical dotted line in FIG. 2. Obviously, inside the corresponding section, the ideal position target value x* is monotonically rising or monotonically falling, and most of them are even strictly monotonically rising or strictly monotonically falling. The direction reversal of the position control shaft 1 will not be achieved inside each section. On the contrary, this direction reversal is achieved from section to section. Therefore, from section to section, the difference between the ideal position target values x* that are directly consecutive in sequence changes its sign. Therefore, if (purely exemplary) each position target value x* in a certain section is greater than (or at least not less than) the immediately preceding position target value x*, then each position target value x* in the immediately following section is less than (or at least not greater than) the immediately preceding position target value x*. On the other hand, it is not important within the scope of the present invention whether the ideal position target value x* (as shown in FIG. 2 ) is positive or negative or partly positive and partly negative.

The control device 4 implements the position control based on the processing (usually in software) of the machine code 6. The structure and function of the position control are explained in detail below in conjunction with Figure 3 for the processing of a single ideal position target value x*. However, it should be pointed out again that the explained steps are respectively repeated at time intervals δt with the corresponding next ideal position target value x*.

According to FIG. 3 , the control device 4 delivers the corresponding ideal position target value x* to the node 8 and the determination block 9. The determination block 9 determines the corresponding additional target value δx*, which is also delivered to the node 8. The function of the determination block 9 will be explained in detail later. In the node 8, the corresponding additional target value δx* is added to the corresponding ideal position target value x*. As a result, the corresponding resulting position target value x*+δx* is obtained.

The control device 4 delivers the corresponding resulting position target value x*+δx* to a further node 10. In addition, the control device 4 delivers the corresponding position actual value x to a further node 10. The corresponding position actual value x can be detected, for example, by means of a conventional position sensor 11, which detects the position of an actuator 12, by means of which the position control shaft 1 is adjusted.

The difference between the corresponding result position target value x*+δx* and the corresponding position actual value x is obtained in the node 10. The corresponding difference (mostly referred to as the adjustment difference in the professional field) will be sent to the position regulator 13. The position regulator 13 can be designed as a P regulator, for example, according to the schematic diagram in Figure 3. However, the position regulator can also be designed as something else, for example, as a PI regulator. The position regulator 13 derives the corresponding first actuation signal v* for the actuator 12 according to the corresponding adjustment difference sent to it. As a result, the actuator adjusts the position x of the position control shaft 1 according to the corresponding result position target value x*+δx*.

It is feasible that the first actuation signal v* acts directly on the actuator 12. However, the control device 4 usually implements a speed regulator 14 according to the schematic diagram in Figure 3, and the speed regulator is subordinate to the position regulator 13. In this case, the position regulator 13 indirectly adjusts the position of the position control shaft 1. In addition, in this case, the corresponding first actuation signal v* is the corresponding ideal speed target value v*. The speed regulator 14 can be constructed as a P regulator or a PI regulator, for example. Other designs are also feasible.

In the case of indirect regulation, the position regulator 13 does not directly transmit the corresponding first actuation signal v* to the actuator 12. More precisely, the position regulator 13 first transmits the corresponding first actuation signal v* to the further node 15. In addition, the control device 4 transmits the corresponding actual speed value v to the further node 15. As a result, the control device 4 can, for example, derive the corresponding actual speed value v, the control device performing differentiation of the actual position value x in the differentiator 16 (i.e. deriving the time derivative of the actual position value x). However, other possibilities are also provided, such as directly detecting the actual speed value v. In the further node 15, the control device 4 forms the difference between the corresponding ideal speed target value v* and the corresponding actual speed value v. The difference formed in this way is transmitted to the speed regulator 14.

The speed regulator 14 generates a corresponding second actuation signal I* for the actuator 12 according to the difference between the corresponding ideal speed target value v* and the corresponding speed actual value v. Therefore, the speed regulator 14 regulates the speed v of the shaft 1 according to the corresponding speed target value v*.

The speed regulator 14 can act directly or indirectly on the actuator 12 in a similar manner to the position regulator 13. For example, according to the schematic diagram in FIG. 3 , it is possible to directly control the actuator 12 according to the corresponding second actuation signal I*, for example, to control the frequency converter in the case of an electric motor. In the case of indirect action, it is possible, for example, that another regulator, in particular a current regulator, is attached to the speed regulator 14. However, this is not shown in FIG. 3 .

According to the schematic diagram in FIG3 , the corresponding additional target value δx* in particular includes at least one first component δx1*. The first component δx1* is only related to the position difference. The position difference is the difference between the corresponding ideal position target value x* and the first ideal position target value x* of the corresponding section of the sequence of ideal position target values x*. FIG4 shows this relationship. The absolute value of the position difference is plotted on the abscissa, i.e., the path taken from the beginning of the method with the current direction of travel or (equivalently) from the most recent direction reversal that has been achieved. The attached absolute value of the first additional target value δx1* is plotted on the coordinate axis. According to the schematic diagram in FIG4 , as the absolute value of the position difference increases, the absolute value of the first component δx1* increases monotonically. In the first region, i.e., until the absolute value of the position difference reaches a predetermined upper limit, as the absolute value of the position difference increases, the absolute value of the first component δx1* increases strictly monotonically. The upper limit itself has a value greater than 0.

Typically, the absolute value of the first component δx1* is constant from the lower upper limit. Alternatively, the absolute value of the first component δx1* can rise monotonically from the lower upper limit to the higher upper limit. In this case, the absolute value of the first component δx1* is constant from the higher upper limit.

Within a segment of the sequence of ideal position target values x*, the first component δx1* uniformly has the same sign. In particular, if the ideal position target value x* increases monotonically, the first component δx1* is always positive according to the schematic diagram in FIG5 . On the contrary, if the ideal position target value x* decreases monotonically, the corresponding additional target value x* is always negative according to the schematic diagram in FIG5 . Therefore, at the transition from a segment of the sequence of ideal position target values x* to the next segment of the sequence of ideal position target values x*, the first component δx1* changes its sign. In particular, according to the schematic diagram in FIG5 , at the end of the corresponding segment of the sequence of ideal position target values x*, a jump to the first component δx1* is achieved, and the first component is assumed to be at the beginning of the next segment. This is represented in FIG5 by two curved arrows shown by dashed lines.

It is possible that the absolute value of the first component δx1* already has a certain, non-zero absolute value at the beginning of the corresponding section of the sequence of ideal position target values x*. However, preferably, the first component δx1* has the value zero at the beginning of the corresponding section of the sequence of ideal position target values x* according to the schematic diagrams in Figures 4 and 5. In addition, according to the schematic diagrams in Figures 4 and 5, the absolute value of the first component δx1* assumes a predetermined maximum value MAX as long as the absolute value of the position difference reaches a predetermined limit. After that, the first component δx1* no longer increases further within the corresponding section of the sequence of ideal position target values, but remains constant. The predetermined limit mentioned corresponds to (depending on the design) a lower upper limit or a higher upper limit.

Different methods are possible within the above-mentioned restrictions. For example, a linear, partially linear or continuously decaying increase to a maximum value MAX can be achieved. The manner and method of obtaining the corresponding first component δx1* is essentially secondary. For example, the functional variation can be defined by means of a table or by means of a function. The table can be filled in with values or the parameterization of the function can be performed, for example, based on operating tests. The input variable in the table or in the function is the ideal travel path programmed from the most recent direction reversal. The output variable is the corresponding first component δx1*.

It is possible that the additional target value δx* includes only the first component δx1*. In this case, it is immediately and obviously derived that, with the first component δx1* within the segment of the sequence of the ideal position target value x*, if the ideal position target value x* increases monotonically, the corresponding additional target value δx* is also positive, and if the ideal position target value x* decreases monotonically, the corresponding additional target value is negative. However, preferably, the additional target value δx* includes (usually and according to the schematic diagram in FIG3 in addition to the first component δx1*, in special cases instead of) a second component δx2*. The second component δx2* is related to the travel speed of at least one axis 1. In particular, the second component δx2* can be proportional to the travel speed of at least one axis 1 according to the schematic diagram in FIG6. However, here, according to the schematic diagram in FIG6 (similar to the first component δx1*), if the ideal position target value x* increases monotonically, the second component δx2* is always positive, and if the ideal position target value x* decreases monotonically, the second component is always negative. The travel speed can alternatively be a target speed or an actual speed, depending on whether the travel speed can be derived from the ideal position target value x* or from the position actual value x or can be directly detected.

The design according to the invention can be modified in different ways and methods. Subsequently, two designs are first explained, which are preferably implemented together according to the schematic diagram in FIG. 7. However, in principle, the two designs can be implemented independently of each other. Then, another design constructed on the basis of the design according to FIG. 7 is explained in conjunction with FIG. 8. However, the additional design according to FIG. 8 can be implemented without the preferred design according to FIG. 7.

According to the schematic diagram in FIG7 , the control device 4 derives the corresponding first pre-control signal δv* from the sequence of the resulting position target values x*+δx* in the further determination block 17. The control device 4 can, for example, perform a differentiation of the resulting position target values x*+δx*, i.e. derive its temporal derivative, in the further determination block 17. In any case, the first pre-control signal δv* is derived without taking into account the corresponding position actual value x.

If the control device 4 determines the first pre-control signal δv*, the control device 4 determines the corresponding result speed target value v*+δv* by adding the corresponding first pre-control signal δv* to the corresponding ideal speed target value v*. In this case, the speed is regulated to the result speed target value v*+δv* by means of the speed regulator 14. The corresponding result speed target value v*+δv* is no longer the same as the corresponding ideal speed target value v*, but it is still related to the corresponding ideal speed target value v*. In particular, the difference lies only in the matching corresponding first pre-control signal δv*.

In addition, the control device 4 derives the corresponding second pre-control signal δI1* according to the sequence of the result position target values x*+δx* according to the schematic diagram in FIG7 . The control device 4 can, for example, derive the differentiation of the corresponding first pre-control signal δv* that has been derived again in another determination block 18 and then derive the corresponding second pre-control signal δI1* by expanding the intermediate signal derived in the multiplier 19. However, it is also feasible to directly derive the corresponding second pre-control signal δI1* without deriving the corresponding first pre-control signal δv* in advance. In any case, the derivation of the second pre-control signal δI1* is also achieved without taking into account the corresponding position actual value x.

If the control device 4 determines the second pre-control signal δI1*, the control device 4 determines the corresponding third actuation signal I*+δI1* by adding the corresponding second pre-control signal δI1* to the corresponding second actuation signal I*. In this case, the speed regulator 14 does not directly supply the corresponding second actuation signal I* to the actuator 12. Rather, the corresponding third actuation signal I*+δI1* is determined in advance. In this case, the actuator 12 is driven according to the corresponding third actuation signal I*+δI1* according to the schematic diagram in FIG. 7.

Furthermore, according to the design of FIG. 8 , the control device 4 derives a corresponding third pre-control signal δI2* in a further determination block 20 based on the sequence of additional target values δx*. The derivation of the third pre-control signal is achieved without taking into account other variables. The control device 4 adds the corresponding third pre-control signal δI2* (in addition to the corresponding second pre-control signal δI1* according to the schematic diagram in FIG. 8 , but in principle it is not relevant thereto) to the corresponding second actuation signal I*. As a result, the control device 4 derives a corresponding final actuation signal in the design according to FIG. 8 , which is used to drive the actuator 12.

The position difference values of the respective first components δx1* from which the respective additional target values δx* are derived so far correspond to the difference between the respective ideal position target values x* and the first ideal position target values x* of the respective sections. However, it is alternatively possible that the position difference values correspond to the difference between the respective ideal position target values x* and the respective position actual values x. In this case, in addition to the respective ideal position target values x*, only the position actual values x must be conveyed to the determination block 9. The remaining derivations can be retained without any changes. FIG. 9 shows this in a corresponding modification of the design scheme according to FIG. 8. However, corresponding modifications are also possible in the designs of FIG. 3, FIG. 6 and FIG. 7.

Therefore, in general the present invention relates to the following facts:

The control device 4 of the machine presets a control command C, which determines a sequence of ideal position target values x* for the position control axis 1 of the machine. The sequence has consecutive sections. Within the section, the ideal position target value x* increases monotonically or decreases monotonically. The direction of monotony changes from section to section. The control device 4 implements the position regulator 13 and according to the sequence of ideal position target values x*, the control device 4 transmits the resulting position target value x*+δx* and the actual position value x to the position regulator 13. The position regulator 13 thus derives an actuation signal v* for the actuator 12 of the axis 1, and the position regulator thereby adjusts the position x of the corresponding axis 1. The resulting position target value x*+δx* corresponds to the sum of the ideal position target value x* and the additional target value δx*. Within the section, if the ideal position target value x* increases monotonically, the additional target value δx* is a positive number. If the ideal position target value x* decreases monotonically, the additional target value δx* is a negative number. The additional target value δx* includes a first component δx1*, which is only related to the position difference. The position difference is the difference between the corresponding ideal position target value x* and the first ideal position target value x* of the corresponding segment or the difference between the corresponding ideal position target value x* and the corresponding position actual value x. The absolute value of the first component δx1* of the additional target value δx* increases strictly monotonically at the beginning and at least monotonically thereafter as the absolute value of the position difference increases.

The invention has numerous advantages. In particular, deformation-related hysteresis errors and speed-related hysteresis errors can be compensated in an efficient manner. Furthermore, a further measuring system arranged remote from the actuator 12 is not necessary for detecting the (actual) position of the at least one position-controlled axis 1 .

Although the present invention has been illustrated and described in detail by means of preferred embodiments, the present invention is not limited to the disclosed examples and a person skilled in the art can derive other variants without departing from the scope of protection of the present invention.

Claims (13)

1. A control method for a machine having at least one position-controlled axis (1), - wherein the control device (4) of the machine predetermines a sequence of control commands (C) which determines a sequence of ideal position target values for the at least one position-regulating axis (1), - wherein the sequence of the ideal position target values has a plurality of sequentially consecutive sections, wherein, within a corresponding section of the sequence of the ideal position target values, the ideal position target values monotonically increase or monotonically decrease, - wherein the signs of the differences of the ideal position target values are directly changed from segment to segment of the sequence of the ideal position target values, wherein the control device (4) implements a position controller (13) for the at least one position-regulating axis (1), - wherein the control device (4) transmits a sequence of resultant position target values and corresponding position actual values (x) to the position regulator (13) according to the sequence of the ideal position target values, - wherein the position regulator (13) generates a corresponding first actuation signal for the actuator (12) of the at least one position regulating shaft (1) according to the corresponding resulting position target value transmitted to the position regulator and the corresponding position actual value transmitted to the position regulator, and thereby directly or indirectly adjusts the position of the at least one position regulating shaft (1) according to the corresponding resulting position target value, - wherein the corresponding result position target value is obtained by adding the corresponding additional target value to the corresponding ideal position target value, - wherein, within a segment of a sequence of ideal position target values, if the ideal position target value increases monotonically, the corresponding additional target value is a positive number, and if the ideal position target value decreases monotonically, the corresponding additional target value is a negative number, characterized in that, - the additional target value comprises a first component, which is related only to the position difference, The position difference value is the difference between the corresponding ideal position target value and the first ideal position target value of the corresponding segment or the difference between the corresponding ideal position target value and the corresponding position actual value; and The absolute value of the first component of the additional target value increases strictly monotonically at the beginning and at least monotonically thereafter with increasing absolute value of the position difference value. 2. The control method according to claim 1, It is characterized in that As soon as the absolute value of the position difference reaches a limit, the absolute value of the first component assumes a predefined maximum value and then remains constant within the corresponding section of the sequence of the ideal position target values. 3. The control method according to claim 1 or 2, It is characterized in that The first component has the value zero at the beginning of a respective segment of the sequence of ideal position target values. 4. The control method according to claim 1 or 2, It is characterized in that The additional target value comprises a second component which is related to the travel speed of the at least one position regulating axis (1). 5. The control method according to claim 4, characterized in that the second component is proportional to the travel speed of the at least one position adjustment axis (1). 6. The control method according to claim 1 or 2, It is characterized in that - the control device (4) implements a speed regulator (14) which is subordinate to the position regulator (13), the position controller (13) does not directly supply the respective first actuation signal to the actuator (12), but rather supplies the respective resulting speed target value and also the respective speed actual value to a speed controller (14), wherein the respective resulting speed target value is dependent on the respective first actuation signal, - The speed regulator (14) generates a corresponding second actuation signal for the actuator (12) of the at least one position adjustment shaft (1) based on the corresponding resulting speed target value and the corresponding actual speed value, and thereby directly or indirectly adjusts the speed of the at least one position adjustment shaft (1) based on the corresponding resulting speed target value. 7. The control method according to claim 6, It is characterized in that - the control device (4) derives a corresponding first precontrol signal based on the sequence of resulting position target values without taking into account the corresponding position actual value and - The control device (4) obtains the corresponding result speed target value by adding the first pre-control signal to the corresponding ideal speed target value. 8. The control method according to claim 6, It is characterized in that - the control device (4) derives a corresponding second precontrol signal based on the sequence of resulting position target values without taking into account the corresponding position actual value and - The speed regulator (14) does not directly transmit the corresponding second actuation signal to the actuator (12), but the control device (4) derives the corresponding third actuation signal for the actuator (12) by adding the corresponding second pre-control signal to the corresponding second actuation signal and drives the actuator (12) according to the corresponding third actuation signal or according to the corresponding fourth actuation signal derived from the corresponding third actuation signal. 9. The control method according to claim 8, It is characterized in that - the control device (4) derives a corresponding third precontrol signal based on the sequence of the resulting position target values without taking into account the corresponding position actual value and - the control device (4) derives the respective fourth actuation signal for the actuator (12) by adding the respective third pre-control signal to the respective third actuation signal and - actuating the actuator (12) using the corresponding fourth actuation signal. 10. The control method according to claim 6, It is characterized in that - the control device (4) derives a corresponding third precontrol signal based on the sequence of resulting position target values without taking into account the corresponding position actual value and The control device determines a corresponding resulting actuation signal for the actuator (12) by adding the corresponding third precontrol signal to the corresponding second actuation signal, and the actuator (12) is controlled by means of the resulting actuation signal. 11. A computer-readable storage medium having stored thereon a control program for a control device (4) of a machine, the machine having at least one position adjustment axis (1), wherein the control program (5) includes a machine code (6), the machine code (6) being directly processable by the control device (4), wherein the processing of the machine code (6) is caused by the control device (4) so that the control device (4) controls the at least one position adjustment axis (1) according to the control method described in any one of the preceding claims. 12. A control device for a machine, the control device having at least one position adjustment axis (1), wherein the control device is programmed using a control program (5) of a computer-readable storage medium according to claim 11 so that the control device controls the at least one position adjustment axis (1) of the machine according to a control method according to any one of claims 1 to 10 when running. 13. A machine, wherein the machine has at least one position-adjusting axis (1), wherein the machine has a control device (4) according to claim 12, wherein the control device (4) controls the at least one position-adjusting axis (1) of the machine according to a control method according to any one of claims 1 to 10 during operation.